Correction: CMU CS undergraduate program admits 300 each year, 135 enroll. The acceptance rate is around 6%
To throw out some more numbers, the last I got for MIT, which was before a degree from it was perceived as being relatively more valuable in the Great Recession, it received 13,000 applications, 3,000 of which were judged capable of doing the work, and the admissions office aimed for a yield AKA class size of 1,100.